[CentOS] system logs out suddenly

The graphics controller is Intel Corporation 82G33/G31 Express Integrated
Graphics Controller
This problem is occuring since the time I have updated firefox. Also
whenever I open facebook the system hangs and sometimes logs out. But sites
like yahoo, gmail, orkut are opening.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.centos.org/pipermail/centos/attachments/20101102/4c00ad43/attachment.html